The Mystery Folder
by Sorio99
Summary: Sometimes, it's better not to know what's going on. Sometimes, but not always. Spoilers for all endings.
1. Chapter 1: The Memory Files

'Open Directory: Library'

'Open Folder: Application Support'

'Open Folder: AddressBook'

'Open Folder: Images'

'Open Folder: ©åß†´®'

'Run Application: Ø¬∂ ¬å∫.jar'

 **ERROR: This application can not be run on this computer.**

'Run Application: Â´µø®¥ ßø®†´å©´'

 **ERROR: This application can not be run on this computer.**

"Huh."

Sans didn't have much experience with dying.

That is to say, THIS Sans didn't have much experience with dying. Hell, until this morning, he barely had any experience with death, considering the two times he had seen someone die, the deaths were rendered moot by the universe's odd whims. All Sans, throughout timelines and throughout the multiverse, had plenty of experience with death, between Flowey, the kid (or kids, he assumes), or even his own hand, apparently. None the less, Sans had never really DIED, at least that he could remember, before this.

But he was pretty sure you weren't supposed to wake up in bed without so much as a scratch on you.

He had to catch his breath first, make sure he was actually remembering something that happened, and not just some random nightmare. He didn't have them often (thank FOX for that, or his sleep schedule would be even worse), but when he did have them, they usually didn't involve so much…blood. Then again, he's the only monster underground WITH blood at this point, so maybe they should.

No. This wasn't a dream. His journal wouldn't have all this "KILL THE KID" and "27 times" stuff written in it if it were. He'd fought the kid, he'd lost, and he'd died.

So why was he back in Snowdin?

He didn't ever remember past resets, and the only one that had even registered with him in the moment was the one from the surface.

(Calming down Papyrus after that one was a real problem, considering one second he had been admiring the night sky, and the next he was underground in his old racecar bed without so much as a warning.)

Maybe this time was different because the kid killed him? He didn't think dying was the key to remembering beyond resets. Maybe it was because they killed everyone?

He checked his clock. 6:16 AM. The estimated time of the human's fall. And it was the same day, so it probably wasn't a coincidence he woke up now. 6:17 now. He was really back. He actually remembered the reset. He remembered meeting the kid, he remembered watching the fights, he remembered bribing the bot…

He remembered his brother dying in front of him. He remembered Undyne melting away before evaporating quicker than water in Hotland. He remembered monsters refusing to evacuate because this was the only home they had now. He remembered telling Alphys that he had to go, he had a job to do, she could protect the evacuees, she had to-

He remembered bleeding out on the floor of the judgement hall, teleporting just far enough away to feel some semblance of peace, before dusting on his favorite bar stool at Grillby's.

He remembered dying.

God, was this how Papyrus felt?

' _Wait. Papyrus. Shit!_ '

He knew he was forgetting something. Papyrus, from his own perspective, had just been killed by one of the few people to ever call him friend. He needed a million times more support than Sans did at that point.

Sans ran as fast as he could, for an admittedly short distance, before almost breaking the door trying to get in Papyrus's room.

And there he was. He was just sitting there, staring off into nothing, like he was barely even alive. He looked over at Sans, and for the first time, Sans knew what he was going to say before he even said it.

"YOU REMEMBER THIS TIME, DON'T YOU?"

"…yeah. yeah i do, paps."

 **AN: Based mainly on one headcanon, and one AU-ish element. The AU-ish element is kinda spoilery (even if you can pretty easily guess it already), but the headcanon is that Papyrus remembers the timelines and resets, but Sans doesn't. It's not supported much by the game, but it makes things even more tragic.**

 **Also, in case you couldn't tell, this takes place right after a No Mercy/Genocide run, which itself took place after a True Pacifist run. Sans doesn't even notice resets happening most of the time (unlike most monsters who have some Déjà vu or discomfort), but he did notice when the TP run got reset. So Sans only noticed a True Reset. Have fun working that out!**

 **Finally, the folder and application names were basically just me typing the names on Mac with the alt-key held down. In order of appearance, we've got Gaster, Old Lab, and Memory Storage. No points for guessing what THOSE mean.**

 **Will be updated irregularly. Feel free to cuss me out in comments.**


	2. Chapter 2: The Missing Followers

**AN: A bit longer this time, and a lot more explanation-y. Get ready for some oddly phrased exposition!**

'Open Directory: Library'

'Open Folder: Application Support'

'Open Folder: Steam'

'Open Folder: steamapps'

'Open Folder: common'

'Open Folder: Undertale'

'Open File: Undertale'

* * *

Sans wasn't entirely sure how this place was still around. After all, even their old house seemed to have disappeared, along with everyone and everything to do with the old man. Nonetheless, here it was, hidden behind walls in the Core only someone who knew the place inside and out would have noticed seemed conspicuously unused.

To say it looked like Alphys's lab would be an understatement. It basically WAS the same lab, just with a few extra rooms and about 23% less liquid monster on the beds. There were, of course, smaller differences; the computer instead of the TV and VCR, the DT extractor being to the east, instead of the west, and a few pictures scattered about of three happy looking skeletons. Other than that, though, it was largely identical, and Sans doubted that was a coincidence.

 **ERROR: Files cannot be opened without Admin permission**

And there it was again. He couldn't so much as look through folders without some hole in the code to wriggle through. Still, at least he could watch and work out how exactly the creep running this show went about their business.

The game had been started up. Sans noticed the clock on the top-right of the screen move a lot quicker, as seconds became seconds instead of frames. Oh well, the kid had barely made it past Napstablook. He had plenty of time to get to his post.

They were apparently going for a neutral ending this time-or at least, they hadn't bothered to grind out the monsters in the ruins before fighting Napstablook. Who knows, maybe this time the kid'll spare Toriel and Papyrus. He could only hope.

The creep had deleted some file in some folder a while back. Sans was fairly sure that was supposed to keep track of whether or not they'd done a certain run, but he wasn't sure which one, since, again, he couldn't actually open any files for himself. Still, he remembered, Paps remembered, and his journal remembered, so that was all that mattered.

It was about time to head out. He had a few gold to hide in a Snow Poff.

As he got ready to leave, he noticed the desktop wallpaper on the creep's computer. (The desktop itself was absurdly messy, but that was hardly the creep's worst crime.) It was a pic from when the gang got together up on the surface. Apparently, the kid kept it, and Tori called him a week later and mentioned that Frisk had scribbled over everyone's face except their own, where they had drawn a creepy smile. He pointed out that the smile only looked creepy because everyone else had been de-faced, and the kid had probably been trying to give them smiles but got frustrated when they messed up.

He didn't believe a word of that, but Tori had believed it, and that was good enough for him. At the very least, the kid didn't have a chance to do anything before they went back to the start, so they weren't a very effective murderer outside the underground. Assuming they intended to do anything to begin with.

Wait. He looked back at the computer one last time.

The desktop was some generic galaxy wall-paper that probably came with the computer. Why did he think it was the picture?

He shrugged it off. It was far from the craziest thing he'd ever imagined seeing.

* * *

It was the girl that had convinced him to leave.

She was related to Dr. Tate, he believed. A niece? A cousin? Whoever she was, she didn't deserve this sort of treatment.

He'd stormed in while the doctor was making another mindless entry about the results and given him an ultimatum; stop the experiments now, let the kid go home, and give up this notion of "undoing past mistakes", or Sans was out. It was…less effective than he would have preferred, but at least he could still look himself in the mirror and say he was a good person.

After he left, he heard a series of assistants came in to replace him. Some big, some small, some thin, but all unprepared. They apparently left as well, after they realized what all the doctor was doing.

The only one who stuck around was Dr. Tate, and she had her own issues to deal with. Still, considering how things turned out, she was the lucky one, since at least she was still around after the "accident". Of course, maybe if HE had stuck around, the "accident" wouldn't have happened at all.

He doubted it. Programming was always Alphys's wheelbarrow, not his. It's not his job to make sure the subject doesn't clip through the floor.

* * *

It was a long night, that first reset.

Or rather, it was a long morning. Day, even, since the kid showing up just drove home that this was really happening.

The talked for hours about various subjects, though it always revolved around the same pachyderm. "What happened after I died", or "How do we remember this at all", or just "I'm so happy you're alive". It didn't help that occasionally, out of the corner of his eye, Sans would see that damn demon holding the glove that took his brother from him.

Still, let bygones be bygones, especially since the kid was extra merciful this time around. If Sans didn't know any better, he would've assumed that they were trying to atone for their past mistakes.

Of course, he did know better, and two runs later the kid had killed everyone yet again. He was tempted to break the cycle and just kill the brat as soon as they left the ruins next time, but he knew that wouldn't help anything. They'd just come back, only now they had reason to attack him.

Besides, unless the kid was a real quick maniac, he wouldn't be able to do much damage to them anyways. That's the problem with calculated Karma: it doesn't really account for possible futures.

Ah well. At least now he knew, if they did kill his brother, he'd get a chance to see him again outside whatever afterlife awaited them.

* * *

 **AN: Like I said, a bit longer this time. In case it wasn't clear, the Karma system in this fic is related to the accused's LV, so someone at LV 5 would be less damaged than someone at LV 19.**

 **Also, the sections are more than a little out of order, but Sans's whole life is pretty out of order, and I felt like this flowed a little better. Feel free to correct me if I'm wrong.**

 **Lastly, the picture appearing as the wall paper? Yeah, that's meant to be a legit hallucination. The man's tired and traumatized, what can you do?**


	3. Chapter 3: The Master Fell

**AN: BACKSTORY TIME! More oddly phrased exposition incoming. Hopefully this chapter makes more sense than the last one.**

'Open File: file0'

'Alter Value Line 5'

 **Current Value: 0**

'Set Value: 99'

* * *

DropEmptysquareShadedcircleScorpioDiamondAquariusPiscesSquareCapricorn PiscesSmalldiamond DiamondScorpioShadedsquareShadedSquarePiscesLeoCircleBoxeduparrow SmalldiamondShadedsquareEmptysquareSquareCapricornOpenmailbox

* * *

The first thing that drew his attention when he entered the lab was the souls. They were in their containers, as usual, but they were…dimmer. They looked weak and fragile, like at any moment, they would shatter into a million pieces.

The second thing that drew his attention were the warning sirens going off all around him. That probably should have been the first.

He ran into the nearest shortcut to the computer room. (Everyone who worked under the Doctor learned the basics of shortcuts, especially within the lab.) Alphys was there, of course, furiously typing away at the keyboard while occasionally glancing over at the 239 SecCam. As he looked, he saw the Doctor in what could only be described as a turtle-skull injector seat. He barely heard Alphys as she explained what was going on, though he could make out a few key points.

"The determination…no overload but there's…I didn't take the floor…directly over the CORE…"

He didn't need to hear anything else. He switched the door's exit point to Room239 and ran out, while Alphys started screaming something about…broad range spells? He's fairly certain he's remembering that wrong, but that wouldn't make much sense either.

He got the and saw the Doctor writhing. Now that he was up close, he could see every hole in the "skull" held a full vial's worth of liquid DT. Meanwhile, in front of the seat, a small panel showing time codes and location coordinates glowed brighter than the souls the liquid was taken from.

It's a funny thing, determination. None at all, and a monster's body falls to pieces. Too much, and a monster's body melts into a slurry of liquid dust.

Within each vial combined was enough determination to melt the entire underground.

He wished he could say he had started pulling out injectors as soon as he saw, or pulled the man out of the chair, or done ANYTHING proactive, but all he did was gawk as his teacher pumped himself full of determination.

It wasn't until he heard Alphys over the intercom that he got shaken from his shock.

"WHAT ARE YOU DOING, SANS?! GET OUT OF THERE NOW!"

(Far a split second, all he could think was "she sounds like papyrus")

By the time he grabbed an injector, though, it was too late. The doctor opened his eyes and

the next thing Sans knew, he was 5 years old in a ramshackle hut with his brother, and no one in the world had ever heard of Doctor W.D. Gaster.

* * *

"SANS! WHY DO YOU HAVE TO SAY THE SAME JOKES EVERY TIME?"

"i dunno. why do you always act surprised to see a human?"

"BECAUSE THE HUMAN EXPECTS ME TO BE SURPRISED! WHAT WOULD THEY THINK IF THEY DON'T REMEMBER, AND SUDDENLY A SIX-FOOT-TALL SKELETON WALKS UP TO THEM AND ACTS LIKE THEY'VE MET 65 TIMES BEFORE?"

"well, what would they think if they _do_ remember, and the laziest guy in snowdin suddenly changed what he said with no prompting?"

"ARGH! WHATEVER! DID YOU AT LEAST CHECK THEIR EXP?"

"yep. perfect zero. we're dealing with a pacifist so far."

"WELL THAT'S GOOD! I AM SO SICK OF GETTING CUT DOWN."

"well, maybe i can help you cut up."

"…SANS, WHAT DID I SAY ABOUT PUNS REGARDING OUR UNTIMELY DEMISES?"

"was it along the lines of 'cut it out'?"

"SANS!"

* * *

Íøµ´†˙ˆ˜© ˆß †´´®®ˆ∫¬¥ ∑®ø˜©

* * *

Judges underground were…different from other monsters. They occasionally took long breaks in the middle of activities, and they had free reign pretty much anywhere in the kingdom. But the most important thing about judges, for the Royal Science Academy, at least…

Was that they bled.

This was because the procedure to become a judge involved rituals to make the subject more "human"-like. After all, only humans could "CHECK" people, and such an ability is almost perfect for judging criminals. How can you hide your crimes when it's written right on your face?

The judge at the time was an older lady named Apo Crite. Sans noticed she looked similar to the depictions of wasps in his textbook. Her problem that day was a pain near her stinger. That was another thing that made judges different: they could get sick, so every slight pain turned them into a hypochondriac.

Gaster ended up removing a particularly large splinter from her posterior (after vigorous blushing from Alphys, of course) and advised she not sit down for a few hours. What he ended up focused on, however, was a few areas of the splinter that had been painted near red. Apparently, this was the first time Gaster had obtained even a single drop of monster blood.

Sans didn't really understand how that was possible (he had been royal scientist since before the Tragedy of the Royal Family, how did none of the judges since then ever get injured?), but he didn't question it out loud. He was more focused on the theoretical subjects at the time.

It was only when Gaster got the drops under a microscope that he started getting interested.

"what, exactly, am i seeing here, doc?"

"The numbers, Sans! The way they move, the way they change- "

"yeah, i can see that," Sans said, moving away from the viewer, "but what the hell does it mean?"

"It means everything!"

He jumped back at that. Gaster could be passionate, but he very rarely got frustrated. He'd taken hundreds of pictures, and given them to everyone who worked in the lab, and he still had no idea what was going on. Sans would've pitied him, if it weren't against the rules.

"I just don't understand. Why would the blood be filled with numbers and letters? How does it even work as blood? Why does it look red from a distance, but lose its color up close? How- "

"It's code." That got his attention. Gaster stopped his rant to gaze at his secondary assistant. Dr. Alphys Tate, dual major in Comp. Sci. and Theoretical Physics. Sans grinned. If anyone would know code, it would be her.

"It's the code for Ms. Crite," she continued. "It details things like her appearance, or her abilities. It's like DNA, only broader and more directly laid out."

"So, what do you propose, Dr. Tate? That Her Honor Judge Crite is secretly a robot in disguise?"

"N-no, Doctor. I-I'm proposing, or rather suggesting, th-that maybe she's…a video game character?"

If Sans weren't wearing his "Sensitive Material Seriously Don't Let It Touch You Even A Little Bit" gloves, he would have face-palmed. Gaster, however, seemed intrigued with the idea. Eventually, he took the tiny vial containing the rest of the liquid and handed it to Alphys. "When you get a chance, take a look at this 'code' and see what all it says. Perhaps, if it is fruitful, we may reverse engineer it, for better or for worse."

Alphys took one look at the vial, one look at Gaster, and ran off, likely to examine the blood closer.

Sans had never seen blood before that day, but he knew he didn't like it.

* * *

The kid was on their best behavior.

They weren't just merciful, they were FRIENDLY. They laughed at Snowdrake's jokes, they gave IceCap some more personal self-worth, and they even gave Gyftrot a gift after taking the decorations off him. The kid was a down-right saint, only slightly brought down in Sans's eyes by the fact that they had killed his brother over 25 times.

Still, he wasn't worried. He was trained in pattern recognition, and he noticed a lot of patterns with this kid. They wouldn't kill Mettaton unless they'd already killed two major figures, they never killed Vulkin unless they were on a Geno-run, and most importantly to him, they never killed Papyrus unless they'd killed Toriel first. It made sense-Toriel was at least able to kill them, even if it was by accident. Papyrus never killed, even when it would be the only way for him to survive.

Sometimes, he wondered what it would take. Would seeing Sans die do to Papyrus what the opposite did to Sans? His guess was no-at least, not a Papyrus who knows about the resets. He would be angry, and sad, and near hopeless, yes, but he would still be willing to forgive the kid. He would give them one last chance, and then another, until finally the kid just killed him. And even then, he would go out saying there was still one more chance.

Man.

His brother is the coolest, huh?

* * *

.gnorw ylbirret si gnihtemoS

* * *

The results were shocking.

Everything- underground, the surface, maybe even the afterlife- all of it was a simulation.

And it could run on a MacBook.

He would have laughed if it weren't so terrifying.

Gaster, of course, told the king, and explained just how this could benefit everyone. They couldn't alter major parts of the code, unfortunately, but they could change a few things underground to make life easier. Change how doors warp each monster, and suddenly you had teleportation. Who needs the internet when you can communicate through comments in the code? Within ten years, EVERY monster could have a personal device that could alter reality at the push of a button.

Of course, Asgore suggested waiting to reveal the discoveries until more research had been done, and Sans agreed. Besides, everyone able to change the universe just to get next door quicker? Even Sans wasn't that lazy.

(Sans often looked back on that moment, particularly when teleporting from his house to Grillby's.)

Of course, it wasn't long before they found out some more…shocking things. It wasn't just a simulation, but something akin to a game. There was no player, yet anyways, but everything was coded to treat the humans who fell down as player characters in a strange RPG. This wasn't too surprising, either, since this just expanded on the simulation idea.

What was surprising was the SAVE mechanic.

Any entity, with sufficient determination and a small amount of magic, could not only save and reload after death, but reload and reset the whole world, essentially at will. It wasn't even limited to one species! Sure, humans would have an advantage, given their natural higher tolerance for DT, but they would need to, at the very least, pass through the barrier to gain enough magic to access it. Based on the phrasing, even inanimate objects could do it, provided they were given the resources necessary.

It was impressive, of course, but it was also scary as hell. All seven humans to descend since the sealing, including the lost Human Dreemurr, could have turned back time whenever they wanted, and nobody would ever realize it, including the human! Thankfully, the humans apparently all lost determination before they died, but it was still terrifying to think days, if not years, could be ripped from your life without you even realizing.

That was probably why Sans showed up to work three days later to Gaster proclaiming he had severed the lab from the time stream.

Try as he might, Sans could never get an explanation of how, exactly, Gaster accomplished such an impossible feat. All he knew was, apparently, no matter what happened, the contents of the lab would persist through every reset and reload. It was unlikely a human would fall down for a long while, but Sans knew better than to question the doctor when he was obsessing over something.

Then the doctor revealed what he was obsessing over.

Turning back time, reloading a save from before they knew saves existed, undoing everything and going back to a point before. It was pitched as a way to get every monster out of the Underground; go back to before the war, and either win, or prevent the war entirely.

Sans didn't buy it for a second.

Sure, it seemed possible, since there were still a few monsters alive from before the war, but the simulation wouldn't allow it. Pretty much everything before the raising of the barrier, and even a fair amount after it, was treated as a preset constant, and it wasn't even accessible to any "player". No, if you wanted to reload, you'd have to do it to a point between the present, and the sealing. There was no way out of the Underground without all seven souls. There was no way to prevent this tragedy.

But there was a way to prevent _personal_ tragedy.

* * *

He always watched the fight.

He knew he didn't have to, and a few times he didn't want to, but he always watched.

He wanted to know, right then and there, if his brother was gone.

He would scatter the dust on the scarf, and since that second reset, he would wear it for the rest of the run.

To "KEEP IT WARM", supposedly. Like fabric's temperature persists beyond timelines.

He shouldn't have anything to worry about. The kid had fought Papyrus 65 times before this, and unless they came in with EXP, they never killed him.

But there was a first time for everything.

* * *

Something is terribly wrong.

* * *

They excelled, but they couldn't deny it was privilege. How could it not be, when their father was so important?

Papyrus was set to be head of the Royal Guard. He certainly deserved it, being the strongest of his class, even beating a young warrior woman who was four years his senior.

Sans, meanwhile, would be the next Royal Scientist. Sure, his major was different, but Theoretical Physics was just as valuable for monsters as Biology and Chemistry. Besides, he was top of his class. Of course he was, after the hundreds of special classes his father payed for.

The previous position holders were retiring in two days, to spend the rest of their days in quiet piece.

Of course, things never play out quite like you think they will.

* * *

He saw the kid curling their fist inside the glove. It wasn't a big deal. Papyrus had HP and DEF enough to take a few hits from a tough glove.

* * *

 **Something is terribly wrong.**

* * *

It was a group photo, the former heads and the future heads, together right before the passing of the torch. It was meant to be one last pleasantry before the transition.

* * *

He was just being paranoid. Papyrus would be fine. Everything would be alright. Everything was alright. Everything IS alright.

* * *

 ** _Something is terribly wrong._**

* * *

The Gaster Blasters were just decoration, an intimidation tactic. They couldn't even activate without someone manually turning them on.

* * *

He checked the kid's stats, just to be save. Nothing could have changed, right? All they'd done was change their equipment.

* * *

 ** _Something is terribly wrong._**

* * *

Papyrus was the only one who saw it activate.

He was trained for emergencies, so he did what he was trained to do: assess the situation.

As it was, only Gaster would be caught in the blast. It was pointed square at him, but a quick scan showed it was powerful enough to kill him within the time it took to deactivate it.

Time to react: 3 seconds.

Time to reach Gaster: 3 seconds.

Minimum unavoidable casualties: 1.

He could have saved himself, but he wouldn't. He wasn't that kind of person.

Besides, this was his father.

* * *

 **"** **Chara"**

 **LV 1**

 **HP 20/20**

 **AT 99 (5) EXP: 0**

 **DF 0(7) NEXT: 10**

 **WEAPON: Tough Glove**

 **ARMOR: Manly Bandana**

 **GOLD: 1066**

HOW THE HELL DID THIS KID GET SUCH HIGH ATTACK?!

* * *

 ** _SØM´TÓI˜G ˆS ˇE‰RˆBÒY „RØN˝_**

* * *

Papyrus had just pushed their father out of the way when the beam hit him.

Later analysis indicated that the entity who activated the blaster had an attack stat of at least 38. If Papyrus had been a millisecond slower, both of them would have been dust by the time it was deactivated. Instead, Gaster fell to the ground as his eldest son was demolished by the blast.

Sans couldn't speak. He could barely think. It wasn't until after Gerson had turned off the blaster he finally said something. And then he couldn't stop.

"no.

"no, no no no. no no no no no no no no no no no no noNONONONONONONONONONONONONONNONO!

"PAPYRUS!"

* * *

 **HP: 0/680**

For once, Papyrus seemed speechless. In one hit, this kid who, just ten seconds ago, hadn't so much as touched another living being, had taken off ALL of his health, and then some.

Sans was shocked. He was astonished. He was flabbergasted. He was a whole bunch of other silly words that didn't properly convey that his brother had just been killed in one hit from a merciless demon who just a minute ago had seemed like a pacifist.

"W-WELL…THAT'S…NOT…"

He was dust before he could finish his thought.

* * *

 **AN: So, this chapter was a little dense, huh?**


	4. Chapter 4: The Mourning Fool

**AN: A bit slower this time. Enjoy.**

'Open File: Ø¬∂ ¬å∫'

 **ERROR: File cannot be run on this system.**

'Open File: Troubleshooting'

 **ERROR: File has been corrupted, and cannot be opened.**

'Run Diagnostics'

 **NO ERRORS FOUND**

* * *

This part of Waterfall was always quiet. He wasn't sure if there just wasn't any way to get up here, or if something about the water made everything melt away, but it was always where he went to calm himself.

Unfortunately, it didn't always work.

He had tried to stop it before. He had psyched himself up, saying there was no way Papyrus would be hurt again, not on his watch, he'd stop them this time.

But every time they landed that last blow, all he could see was his brother, fading away after the accident. He'd freeze up, he'd panic, and by the time he calmed down enough to even THINK of getting to the kid, they'd have already left.

He sat there, on the edge of a river, with his head in his hands and his arms on his knees, wondering how the hell he could have been so stupid.

 _'_ _stupid stupid stupid stupid stupid stupid- '_

"It doesn't make sense."

He was never ready when Alphys actually spoke up. In this case, though, he could be forgiven, since he was under the impression he was all alone in the "room".

"sorry, what?"

"I-I was watching the fight. Between the human and P-Papyrus."

"…yeah, you too?"

"It just doesn't make any sense," she explained, sitting next to the "comedian". "I've run the numbers, I've double checked everything, and it shouldn't be possible. There's no way their ATK could have been high enough to one-shot Papyrus, especially at the start of the battle."

"i checked the kid. apparently, they had 99 attack, and that's without the glove."

"But that doesn't make any sense! Even if they were somehow at 20 LV, they should max out at 38 ATK, right? Did they even have any EXP?"

"not before the fight."

This made her sigh. "I'm…I'm sorry about what happened. It wasn't your fault, you know."

"really?" Suddenly, he was standing up, and even at 4'8'', he towered over the sitting dinosaur. "'cause i'm pretty sure it's entirely my fault."

"Sans, you- "

"i mean, i was standing RIGHT THERE, and-and all i did was watch, i didn't even say anything, i could've stopped them, i could've helped him, i could…i could…"

He collapsed. He was barely holding himself together before, now he was near the point of breakdown. She laid next to him, and tried to comfort him. "It's okay. Just breathe. Can you do that for me?"

He tried. He knew how (in for 5, hold for 4, out for 6), but it kept catching in his throat.

"it doesn't get easier."

"Hm?"

"watching it happen. i must have seen it a hundred times now, between the kid, and the weed, and…i still can't handle it. i wish i could, but…i just can't."

"I…I'm sorry." She hugged him. Neither of them felt good from it, but they felt a little bit less alone. "It's going to be okay, Sans. I promise."

"heh." He wiped away the liquid coming from his sockets on his jacket sleeve.

"wish i could believe you, alph."

* * *

"So, should I cancel the show?"

He had to think about it for a second. Now that he was in her house, he could see just how much she had already prepared for the…well, the best word was probably deception, but her code word for it was always "show." The posters, the puzzles, even the broken wall. Everything set up perfectly to trick the kid into thinking she was some sort of hero, swooping in to save them from the killer robot. Of course, now that he had explained what was going on, she figured it was probably pointless, if not insensitive, to try to trick the kid into sticking around.

"nah," he decided, "the kid's probably expecting it, and who knows what'll happen if the pattern doesn't play in the same way as before. it's why i still ask them to play along, even if they're going full geno. it just makes more sense to play it safe."

"O-okay then," she stuttered out, "then at least I won't have to give Mettaton any bad news."

"eh, it's fine. he's gonna go against the plan at the end of the core anyways."

"W-WHAT?!"

* * *

"i know what you're trying to do."

"Nice to see you too, Sans, would you like something to drink?"

"don't play dumb, dad. i know what's going on here."

"I'm afraid I don't understand what you- "

"i saw the kid."

"…I see."

"look, dad, i miss him too, but there have to be limits. there's a line you aren't supposed to cross in this job, and you damn near leaped over it."

"Sans, I can assure you, if I can just get the formula- "

"you've hooked a little girl up to a goddamn melting machine! how is that necessary for any of this?!"

"It's for the greater good!"

"no. it's not. and you know it."

"…"

"…look, i miss him too, but i'm not just going to stand by and let you torture a damn child. either you let the girl go home, and never so much as touch her again, or i'm out."

"Sans, surely you can't be serious- "

"i am. i've got all the papers ready. either she goes home, or i do."

"…Very well then. I shall see you at home, then."

"no. i'm moving out, too. i don't wanna look you in the face after what i saw in there."

"…Fine. Goodbye, Sans."

"goodbye, d…dr. gaster."

* * *

Sans hated surprises. Always had, always would. Surprises in a lab meant danger, accidents, possible injuries. Surprises at home meant repairs, therapy, days of work getting things back to normal.

So maybe the whole time-loop thing was a blessing in disguise. After all, if you're just repeating the same day over and over again, you know what's coming, later today, or especially tomorrow.

The call from Asgore, requesting his services to judge the human should they make it to New Home, was expected. He'd answered the same call 62 times before, and it would have been more if he payed any attention during the kid's Geno runs. Still, even if he weren't stuck in an endless cycle, a human underground typically called for a judge to assess the likely damage, and if the royal guard couldn't provide, the official Judge would have to.

So, there he was, in the same hall he'd first died in, waiting for a demon in human form.

Another timeline, he might have stuck to the script, explaining EXecution Points and Level Of ViolencE, before capping it off with a "dirty brother killer" line. After all, the kid didn't exactly deserve his A material.

But no. He needed to know. And he was gonna find out one way or another.

All he had to do was wait.

* * *

 **AN: I said slow** ** _er_** **, not slow.**

 **Also, in case it wasn't obvious, 1: the conversation in the third section of this chapter took place between Sans and Dr. Gaster at some point after Papyrus's death in that timeline, and 2: in this fic, Gaster is Sans and Papyrus's father. I know, shockingly original, right? /sarcasm.**

 **See you guys next chapter, for the reveal most of you who have kept reading have probably already figured out.**


	5. Chapter 5: This Makes Five

'as of reset #59, there are four entities with potential control of the timeline.

the first, and oldest, is dr. w. d. gaster. assuming i'm not just reading my own notes like a goober, you probably don't know who that is. that isn't important. what is important is his control. admittedly, i have no solid evidence of his control, or even his existence. all i have are gaps in people's memories, vanishing grayscale monsters, and the curious luck of the tate and kid families. atonement, perhaps? who knows.

the second is a flower calling himself flowey, formerly known as prince asriel dreemurr. this is the clearest threat, as he is confirmed malevolent and has numerous times committed partial genocide. apparently, he came into existence after alphys pumped a flower with his dust on it full of, what is scientifically known as, a shitload of determination. if he is currently controlling the timeline and i am already dead, then you probably died before reaching this paragraph.

the third is the human kid, now identified as frisk. from what i can gather, the kid intentionally climbed mount ebott in the hopes of dying. unfortunately, they now seem incapable of doing so. during one run in which we left the underground, they confided in me that their control, both of the timelines and their body, is unstable, and subject to change. not surprising, since this is a kid who can make it through the underground without harming a single living being, or kill literally everyone except alphys and her extended family.

that leaves the fourth, who ironically overlaps quite a bit with the third: the first fallen human, currently known as chara, although that seems subject to change somehow (i swear to god, one time, paps and i woke up and the lost human royal was named frisk. then five hours late, the whole timeline reset. i considered not counting that run, but paps insisted). they fell back in the year 201X, so almost a hundred years before i was even born. they seem the most volatile, as when exercising control over frisk's body, they can range from a bit of a nuisance, to a full blown genocidal maniac, and every shade of shit in between. keep an eye on this kid. they're dangerous.'

* * *

If he had payed more attention, he would have seen how big a mistake he had made sooner. Ah well. Hindsight's 20/20.

* * *

"heya. you've been busy, huh?

"...so, i've got a question for ya.

"do you think even the worst person can change...?

"that everyone can be a good person, if they just try?"

"…"

"heh heh heh heh... all right. well, here's a better question.

" ?"

"…"

"ahem.

"sorry.

"let me explain.

"so, normally at this part, i'd let you through. i'd say, 'eh, i'm mad at you, and you shouldn't have killed my brother, but odds are good you'll just reset and he'll be back anyways.'

"after all, you've already proven you can and will take us back from the end of the world, so what do i need to worry about?

"but seeing what you did to him…

"to ONLY him…

"i can't afford not to care anymore.

"so, let me ask you again.

"what the hell did you do?"

'Use your keyboard to type your response!'

"This is new."

"oh, so the silent wonder can speak after all. answer the damn question."

"I didn't think this was possible. I should have done this run sooner."

"what, surprised i grew a spine? me too."

"Well, that and the keyboard prompt."

"…what?"

"The keyboard prompt, the typing. Wait, shouldn't you know about this?"

"keyboard? kid, i don't get the joke but it ain't funny."

"You really don't get it, do you? Do you want me to explain?"

"if it isn't too much of a hassle.

"…chara."

"Oh, no. My name's not Chara."

"what?"

"Well, at this point, the fallen child's TRUE name is basically public knowledge.

"I figured it was more worthwhile than using my own name."

"your own…who are you?"

"I thought you'd figured it out by this point. In your own words…

"I'm a dirty hacker."

"…"

"The world you inhabit is nothing but a video game, designed for players.

"Like me. I'm just a bit more experimental than others. That's all."

"…huh.

"you sure have a flair for the dramatic, huh kid?"

"I'm not a kid."

"nah, you aren't. aren't a monster, either. you aren't even a demon."

"I'm human, the same as the others."

"well, that's debatable.

"still, how does playing a game let you break reality?"

"Oh, I just changed a digit in one of the game files."

"let me guess, your atk?"

"Of course."

"and, why exactly did you do this?"

"Well, I wanted to get through the Papyrus boss fight quickly.

"It was nothing personal. It just takes a while at LV 1."

"i see.

"and you don't see anything wrong with any of this?"

"I'm a little confused at how well your response match what I'm typing.

"But that's nothing an app on my phone can't do. No offense."

"lots taken. so, let me get this straight. from your perspective, we're all just characters in a game."

"Yes.

"A top-down, 16-bit styled RPG, to be specific. On my MacBook."

"uh huh. and that means my words are just appearing in textboxes for you."

"Correct. In lowercase Comic Sans, for the record."

"of course. and you're just typing out responses that i hear coming from a human child's mouth?"

"Right."

"…either this game is really good at processing text, or you're weirdly anal about spelling and grammar."

"What can I say? I'm planning to be an English major."

"now, see, that's something you don't say to a scientist.

"well, i think i got the gist of it. thanks for filling in the blanks."

"I honestly thought you knew. Don't you remember the resets?"

"of course not. nobody but you and the weed do. i just take a lot of notes."

"Whatever. Can I go, now?"

"not so fast, buddy. much as i'd love to watch you leave and be done with it, i'm afraid this is where your playthroughs end."

"Really?

"I can just quit and reset the game, and you won't even remember a thing.

"Unless you're very good at secretly taking notes."

"nah. you can't see it, but i'm waving my empty hands in the air to demonstrate how little i'm writing."

"Then why should I care about you?"

"because if you reset, i guarantee i will make your life a living hell."

"I think I'll take that risk."

'Quitting.'

'Quitting..'

'Quitting…'

* * *

It was obvious. How had they been so stupid?

He assumed that Chara was the one controlling everything through Frisk, but they were just as liable to be tampered with. Of COURSE, there was an outside player. For god's sakes, it was a video game! What use is a game without a player?

The human had just reset. Full reset, too, not just reloading to before the judgement. Apparently, they didn't trust Sans to not pull the same stunt again. They probably assumed Sans was back at home, reading his notes, wondering about the sudden reset without a conclusion.

He wasn't even aware he was lying when he said he didn't remember. He was barely even thinking. But hey, now for once he had an advantage over the creep.

No, Creep wasn't the right word. He'd chosen the nickname when he assumed the entity was just watching events play out for some voyeuristic pleasure. No, he was manipulating them all from the start. Player was too mild, and Hacker just seemed too simplified.

Manipiulator. That worked. The perfect way to describe this new entity, this fifth variable to take into account.

He checked the computer, hoping to confirm a theory.

 **ADMIN CHANGED. Access granted.**

Jackpot. If the manipulator (okay, that was too long, needed to work on that) had any advantage left, it was gone now.

Sans had complete access to the computer. He checked the taskbar, and sure enough, the creep was playing. Still near the start of the Ruins. Perfect. That meant he had time to do something before they expected anything different. He may not be great at coding, but he sure as hell knew how to cause a corruption.

One last thing to check. He scrolled over to the top left corner, with a tiny apple with a bite taken out of it (presumably a logo for the computer company. It was weird, presumably this was the same kind of computer he was running in his world, given the identical name, but the logo was different, and he was fairly certain the company who made it here had nothing to do with apples), and looked to the bottom of the dropdown menu.

'Log Out Alex Campbell'

Bingo.

"okay, then, alex.

"it's showtime."

* * *

 **AN: In case it's not clear, that isn't my name or the name of anyone I know. I just generated the name at random, but apparently, he's a Canadian actor who was in** ** _Dreamcatcher_** **and the Canadian TV Show** ** _Riverdale_** **. No relation to the American** ** _Riverdale_** **, or Archie Comics at all. Apparently, it's a soap opera based in "the Toronto community of Riverdale". Huh. The more you know.**

 **Also, yes, this is pretty much the most obvious twist in the history of Undertale fan fiction, but if even ONE person didn't see it coming, then I will consider Sans's shock to be realistic.**

 **The idea itself was mainly inspired by the UnderPlayer comics (basically, what if a player tried to interfere with the game in a less positive way) with a dash of "Don't You Have Anything Better To Do?" by Rainbow_Sprinkles over on Ao3, but I literally found out this morning that there's a fanfic called "Strange Places" by AyuOhseki with a similar, if not identical plot twist as this chapter. Oh well, hopefully I do something a bit original with it here.**

 **God, I hope that wall of text up there makes sense. If not, I need to work on writing dialogue. Ah hell, I need to work on it anyways.**

 **Make sure you study for finals if you have them soon, folks! Don't be like Alex, wasting your time giving exposition to video game characters!**


	6. Chapter 6: The Manipulator's Foil

Alex wasn't a very superstitious man. He wasn't opposed to a greater being, but he doubted any deity would appear via a piece of wood. He didn't believe in cryptids, he was doubtful of aliens, and as far as he was concerned, ghosts were just people making connections between nothing.

All this was to say that, on top of being a bit of a self-righteous asshole, whenever he was confronted with something that seemed odd or unexplainable, his mind tended to jump to the most "logical" conclusion. For example, when a video game character suddenly starts talking to him directly after he hacks the game in an odd way? Probably just some basic AI the developer put in to freak out any cheaters.

It didn't really matter. All he had to do to avoid it was just not hack, and he could do that easily. He wasn't even really much of a hacker, anyways. He just used a tutorial for changing the game files.

Reset, and everything will go back to normal.

* * *

It was after he left the ruins that something changed.

Flowey was his usual, grumpy self, but Snowdin was almost eerily quiet. There was no music, ambient noise, or even sound-effects. Was it usually this silent? He couldn't remember exactly.

One thing he did remember was Sans creeping up on him, breaking branch and all, so when that didn't happen, he started to get concerned. Nonetheless, when he reached the pointless gate, Sans did walk up behind him.

And then it was a battle.

He barely had a chance to react before Sans brought up his bones and very quickly killed him. In the few seconds he had, however, he did notice that while his HP was still 20, his LV had somehow jumped to 19.

Then his soul shattered.

"…What?"

* * *

It took four times of this happening before he decided to reset.

He even chose to do a more thorough reset, deleting pretty much every file and redownloading them. He didn't want to have to go through the ruins again, only to end up with the same stalemate.

He loaded the game up, named the fallen child "Chara", and started it up.

* * *

He didn't even make it to the second screen of the game.

He saw his character (Frisk, or whatever was in them) on the flowers, he walked down the hall

and suddenly the door led to the True Lab.

"Wait, what?"

He tried going back through the door, but it almost seemed like a wall now. He was stuck in the True Lab.

This was an oddly specific glitch.

He tried to go through the top-right "exit" in the room

and now he was in the judgement hall.

"But that's…I was going…"

Luckily, this time, the door he came through still worked

and took him to the barrier, with Flowey in front of him instead of Asgore.

"How…why…I thought…"

"You think," Flowey said, text box suddenly appearing on-screen, "you are above consequences."

"Wait…isn't that- "

He didn't have time to finish his thought, as suddenly the screen went black, and then

he was in the room from the end of the Pacifist run.

"I'm…sorry?"

"right."

And now, he was back in the battle with Sans, who had his eyes closed.

"How are you doing this?"

"you are a great partner."

Now he was starting to freak out.

He had agreed to Chara's demands the first time through. He had hoped to avoid a jumpscare.

But he'd deleted the only files that marked that run. How was the game calling it up now?

"We'll be together forever, won't we?"

* * *

 _999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999_

* * *

The game automatically closed.

He decided not to open it back up for the night.

In fact, he decided to go to bed for the night.

Screw 6:37 PM.

* * *

 **AN: A bit shorter this time. I have more to do today for college, but I felt the need to get this chapter done.**

 **If I was halfway decent at programming, I would make a version of the little "glitchout" to play. Anyone willing to do so for a fifty dollar Steam Giftcard?**


	7. Chapter 7: The Monsters' Flashback

**AN: Flashback time! Enjoy the change in perspective.**

* * *

 _Entry Number 17_

 _Dark_

 _Darker_

 _Yet Darker_

* * *

Alphys was a decent programmer. After all, her Comp. Sci. major used coding a small game as a major project, and she had made a number of even smaller ones in her down time. She knew the ins and outs of the code, and she was the first person to decipher the strange characters in the judge's blood. She knew her programs.

That didn't mean she couldn't occasionally make mistakes.

* * *

 _The Darkness Keeps Growing_

* * *

The plan was surprisingly simple.

Room239 was desynced from the rest of the lab. The room itself wouldn't go back, but any living entity possessing determination would. Once the reset was activated, anyone in the room would go back to the temporal coordinates listed on the computer. The determination was intended to make the trip easier-determination was the key to SAVEs, after all. It would make sense to take more than a few doses to stabilize the body and soul through transit.

The…injector seat seemed a little odd, but judging by the blasters lying around, Alphys suspected it was a personal preference for Dr. G.

The rest of the lab served as a sort of temporal bunker. Nobody else inside would go back to that point, but it would insure their continued existence regardless of temporal paradoxes. After all, anyone who worked directly with this stuff was at risk if something went wrong here.

Unfortunately, she was the only one still around at this point. Stretch was back home with his cousin refusing her calls, Pip had almost shouted at her the last time she talked to him, and Dan had apparently moved to the ruins to get away from the lab.

At the very least, Mary was back with her family. It took a while to explain what had happened, but they seemed surprisingly understanding. Mary's siblings even though she looked cool, all pale and flowy, so there was that.

Worst comes to worst, at least she wouldn't have to suffer anymore.

* * *

 _The Shadows Cutting Deeper_

'Warning: Insufficient Data At Destination'

"Wh-WHAT?!"

This was bad. Everything was physically present at the platform, but some part of the code was missing. What had she missed? What did she forget?

It took her 1 minute, 52 seconds, and 73 milliseconds to find her mistake.

* * *

 _Photon Readings Negative_

* * *

"what the hell is going on?!"

That would be Sans. He wasn't using his serious voice, so he clearly didn't know yet.

"is there an overflow?

"No, the determination is fine, there's no overload, but there's a glitch. I didn't take the floor's collision detection into account, and he'll be directly over the CORE…"

It shouldn't be a problem for anyone else. The code was somewhat self-sustaining, so within a matter of seconds, it would correct itself. Unfortunately, with that much determination and temporal meddling, Gaster would be experiencing time at 2 minutes, 33 seconds for every real second.

Then Sans dashed out of the room.

* * *

 _This Next Experiment_

* * *

"Wait, you'll be in the area of effect if you…"

She didn't have time to finish her thought before he was gone.

She caught him on Cam. 239. He was just…standing there.

Not moving. Not helping. Doing nothing.

His eye sockets were completely empty.

'13 seconds to departure.'

"No, no no no NO!"

She grabbed the intercom. She couldn't save Gaster, but she could hopefully save Sans.

"WHAT ARE YOU DOING, SANS?! GET OUT OF THERE NOW!"

He didn't listen.

* * *

 _Seems_

* * *

 _Very_

* * *

 _Very_

* * *

 _Interesting_

* * *

 _…_

* * *

0 minutes and 1 second.

He was back. He was here. Everything was okay. He could fix it this time.

0 minutes and 3 seconds.

He started running towards the blaster. If his calculations were correct, he was now precisely one second before it fired. He didn't have time to disable it, but he had time to move it.

0 minutes and 12 seconds.

He noticed he seemed to be ankle deep in the solid steel platform. That didn't matter now. He needed to save his son.

0 minutes and 25 seconds.

The blaster was heavy. No, that wasn't right. It was just slow. Of course it was, he was experiencing time 15200% faster. He needed to push harder.

0 minutes and 59 seconds.

He was knee deep now, and the blaster was only a third of the way off the platform. He was so focused on pushing as hard as possible, he didn't notice the fluffy white dog scrambling away. If he did, he would have noticed it was moving at the same speed as him.

1 minute and 34 seconds.

Halfway off, now. It was getting harder to push, since he was now up to his hips. Just a little more, and it would tip over on its own right before firing.

1 minute and 59 seconds.

He seemed to be descending faster. The blaster was mostly off now, and tilted just enough to barely graze the flag on the ceiling. Just as well, since it was almost finished charging.

2 minutes and 11 seconds.

He looked back at his sons. Papyrus, standing tall, glancing at where the blaster used to be, seemingly prepared to jump into its former path. It would be worth it, just to save him.

Sans's eyes were staring right at him, and they were the only thing he could see moving as fast as he was.

2 minutes and 32 seconds.

His eyes finally fell below the top of the platform. He could see through it, though. An interesting development: while the simulation itself was presented as a top-down, 2D affair, they experienced it in three dimensions, and from a first-person perspective no less. Something to investigate, if he survived this drop.

2 minutes and 41 seconds.

And he was out of the platform. Looking down, he realized he must have started falling faster because his feet were no longer within the platform, but in fact, under it. Now he was in free fall.

It didn't matter. Both his point of departure and his point of arrival were protected. Alphys would survive. Asgore would survive. Gerson would survive. Sans would survive.

Papyrus would finally survive.

3 minutes, exactly.

The lava was surprisingly cool as he was submerged in it. Of course it was. After all, heat was merely the vibrations of molecules, and he was moving far faster than any of those vibrations.

He was prepared to burn, or even boil, as he descended through the lava.

He didn't expect to fall into a black, inky void, complete with a giant face staring directly at him.

His brain was moving a mile a second. The core was directly powering his experiments. The lava around it had been filled with magic from the second he had built the device. On top of that, his unique situation would make him quite eligible for some out-of-code experience.

He gazed up at the face, this strange being, perhaps his creator, perhaps his destroyer, and he heard it speak thusly:

"Hmmm…nah, I think I can write him out. I hope Temmie's okay with that. Maybe Alphys could work for his role…"

And just like that, he ceased to be.

* * *

 _What Do You Two Think?_

* * *

The first thing she realized was that she was in a lab.

The second thing was that, although it looked like her lab, it most assuredly wasn't.

The third thing was that she suddenly had years' worth of brand new memories, most revolving around a soft-bodied skeleton named Doctor WingDin Gaster.

Then, and only then, did she notice Sans standing right in front of her, working on some kind of computer.

"…What the hell is going on?"

 **AN: So, another chapter down the hatch. Hopefully, this wasn't too bad, since it slightly veers away from the main plot, but the last part did bring it back to the continuing issue from before, albeit in a way that will only make sense next chapter.**

 **Also, I finished school for the semester! YAY! Now I have very little reason NOT to work on this! Aside from, you know, being kinda terrible.**

 **See you next time.**


	8. Chapter 8: The Mystery Folder

**AN: The point the story has been leading to. I hope it's up to your standards.**

 **Though those standards may be pretty low if you're reading my stories.**

 **Also, apologies to that one person who bookmarked this on Ao3 with "yay for universal hacker sans!" You'll get why soon enough.**

* * *

'time dilation and us: a crash course.

'as a result of our universe's unique position, we are inherently connected to an outside universe, heretofore referred to as observer's/player's universe, or opu. if you've read my journal this far, you probably already know about it.

'now, thanks to a specific computer in a lab buried in the core, we can actually make limited observations of this universe. in this section, we'll be going over the clock observed here.

'for the record, as of writing this, everything here only applies to the lab. when opu is not connected directly to our universe, everything outside the lab sorta ceases to exist. it's an existential nightmare, but what are you gonna do?

'in the lab, time continues passing when the universe is unobserved, and at an alarming rate. by my calculations, for every second that opu experiences, the lab experiences a full minute. that may not sound like much, but it means that after two hours in opu, almost a week will have passed in the lab. it sounds crazy, but it's true.

'when i have successfully made it to the lab before the pausing point, i've observed that the observer spends at least eight hours every day, not only away from our universe, but away from their computer in general; usually, they are gone for even longer stretches.

this means that, if you're in the lab, and the observer is gone for the day, you have twenty days to do anything you need to do.'

* * *

UNDERTALE V2.01 (C) TOBY FOX 2015-2017

* * *

It was a lot.

It was easy enough to find the files themselves-hell, he'd seen the asshole open them before-but finding and understanding were two entirely separate things.

He had a basic knowledge of coding, obviously. On top of programming stupid stuff just for fun, everyone in the lab was required to take a crash course in programming once the "universal code" was found. He could manipulate doorways easily enough, mess with graphics, and even call up specific lines from the game itself. In other words, he had just enough computer knowledge to screw with anyone trying to play the game.

He didn't have enough to program an entire universe into a game.

"what did alphys always say…comment well, comment often. maybe…"

He went scouring the code for any comments he could find. Maybe they could help him make sense of all this jargon.

He wasn't entirely disappointed.

* * *

/*

Greetings.

I am the fallen child.

The first human. The second heir.

The youngest Dreemurr.

My true name is Chara, though you may know me as something different.

I apologize if you are confused. That is not my intention.

I merely wish to ensure punishment is sufficiently ensured.

The human in possession of this game made a deal with me.

I intend to make him keep it.

I assume, since you are reading this…

You must be Sans Aster?

It is a pleasure, Doctor.

I apologize if my actions have caused you emotional distress.

Both in aiding the human scum who agreed to exterminate you and your family…

And in preserving your memories beyond that run.

If you wish to know how I did so, simply go to:

Library/Application Support/AddressBook/Images

There you will find a folder containing your answers.

As for why I preserved your memories…

The penultimate strong memory I have.

Before reducing this world to dust, however temporarily.

Was of your resistance.

If anyone can stop this, it is you.

Good luck.

Sincerely,

Chara Dreemurr

Demon.

*/

* * *

If Sans weren't emotionally stunted by both clinical and situational depression, he probably would've been more terrified by the Demon specifically asking for his help than having next to no help with this wall of code.

Nevertheless, he checked the folder the comment specified, only to find a new folder. At first, the text beside it appeared garbled, but it quickly corrected itself:

'Gaster'

He opened the folder, and inside it were two new files, similarly named and corrected:

'Old Lab' and 'Memory Storage'

Booting up 'Old Lab' seemed to just open a window observing his current location in the lab. It was slightly disturbing, seeing himself on the screen like this, but it wasn't anything he hadn't seen before.

(He was a little surprised to see the clock on the top right of his display stay as slow as before. Maybe this application didn't slow down their universe like the main game did? He honestly never understood why that happened anyways.)

So that only left 'Memory Storage'. He opened it up and

inside was the name of everyone he had ever known.

Alphys, Asgore, freaking Burgerpants, every monster in the underground. The only ones conspicuously absent were Frisk and Chara, which explained at least one part of this bizarre situation.

Beside each name were a series of buttons, most of which were unfilled. "Memory Persistence." "Gaster Memories". "Déjà vu". The only one seemingly NOT connected to memories was the last switch: "Lab Presence". If he had to guess, it meant whether or not the respective monster was in the Old Lab itself at the moment, especially since his was the only one which was on in that column.

(He was also the only one listed under "Gaster Memories". He considered changing it for Papyrus, but based on past conversations, Paps wasn't too keen on regaining those specific memories.)

He knew the obvious choice was Alphys. She could parse through the code, she could help him understand, she could even offer some new insight on the situation.

But should he? He had almost three weeks to figure something out, and probably more, and he had a pretty good idea of getting away from the computer as fast as possible. Bringing Alphys in would just drain her, and maybe even break her. Could he do that to her? Should he?

He took a step back. He looked around. Frisk and Chara barely existed at the moment. Gaster may not be fully gone, but he sure as hell wasn't existing. And the player had probably gone to sleep, judging by the 9:36 PM in the top right corner.

It was just him.

Alone.

With the universe sitting right in front of him.

The most important person in the universe was a 37-year-old, depressed, overweight skeleton with an affinity for bad puns and greasy foods.

He hit every button Alphys had.

* * *

"so, that's basically it. world's a game, we've got to fix it, and i need your help."

"O-okay, but why did you restore my memories of your-of Dr. Gaster?"

"simple. back then, you studied this stuff a million times more than dad and i combined. we need you at top form."

"You don't seem too concerned about all of this."

"honestly, i'm just shocked i didn't realize it earlier. i mean, it seems obvious in retrospect."

"O-okay, I'll take a look at it, but I don't think I can make any real progress in a single night."

"nah, no worries. we don't have to worry for over two weeks."

"W-what? W-why?"

"…here. read this entry in my journal. it should explain everything."

"O-okay…Sans, why do you write like somebody other than you is reading this?"

"because you are."

"…Ugh."

* * *

By day two (or around 10:24 PM), they'd worked out a plan. In order of last to first:

Step 3) Remove the game files from the computer and ensure they couldn't be reinstalled. Simple enough, they just had to create a series of files that would cross-reference each other and remove any programs with the game's code in them. (It ended up taking them two full days of work. Alphys expected it to take even longer.)

Step 2) Find a server which could host an active simulation and upload the files to it. Also fairly simple, and they got it done within a matter of minutes.

Step 1) Recode their entire universe to be self-sustaining and stable without any player entity.

That was where the real trouble was.

* * *

As it turned out, there was a reason the two "humans" weren't listed in the Memory Storage: they didn't properly exist. While Frisk's body was "alive" and controlled by the player, both of their conscious minds were relegated to subroutines, only supplying narration and choices in battle. They did, however, emerge under two circumstances: Frisk would take control of their body after a "True Pacifist" playthrough, and Chara would emerge and gain control over a fair amount of the game's files after a "Genocide" playthrough, and any subsequent Pacifist playthroughs. Thankfully, for these scenarios, both children were given full and complete personalities, so it was just a matter of giving Frisk control of their body from the start, with Chara latched to their body as a guide.

(If Sans were honest, he would say he wanted to remove Chara entirely. Alphys talked him out of it, though. After all, two heads are better than one.)

There were also far too many ambiguities in the code for their liking. It made sense for a video game, especially one that never progressed even a year past the end-point, but for a simulation that could hopefully result in a "happy ending", it was far from ideal. They managed to sort through most of them, giving what they thought would be best for everyone (the Royal Guard executed the past humans instead of simply capturing them, simply falling into the Core wouldn't be enough to erase your existence, and Papyrus could actual make edible food if he tried hard enough).

They spent a week and a half just working on the code. They would trade off, between the two of them, with Alphys tutoring Sans on the finer points of programming all the while. It was a little exhausting, especially since neither of them were willing to sleep in fear of losing time, but they managed to get it done.

There were a few things they couldn't make perfect without completely dismembering the universe, unfortunately. They couldn't make Flowey nice, or erase the problems with the DT experiments. Chara would have to be more than a little "abrasive" when they first woke up in the Ruins, and Frisk wouldn't have any idea what was going on at first, but hopefully they could keep each other in check. Besides, he knew Frisk would try to do the right thing. That's just the kind of person they were.

They're universe was safe. Now it was just time to add the final touches.

* * *

"and that's it. thanks so much for your help."

"N-no problem. Sorry if I was a little too anxious while we were working."

"nah, i get it. sorry if i was too sarcastic."

"Yeah, like I'm never sarcastic."

"woah, steady, you don't want to blow up mettaton when you get back."

"I wouldn't worry about that. I mean, I'm not even going to remember this, right?"

"i mean, you could. if you want to."

"…Sans, no offense, but I've seen what this knowledge has done to you. I already have diagnosable anxiety and depression. Knowing our entire universe is just a reprogrammed RPG? No thank you."

"fair enough. so, no memories from gaster's universe either, then?"

"Yeah. Besides, you need SOMETHING to keep you unique."

"what, won't my stunning personality do that for me?"

"Maybe if you stopped making puns, it would."

"hey, i haven't made a single pun since you got here."

"…No, you really haven't. What's up with that?"

"eh, it's not as much fun when the only other person around actually likes them. plus, i got enough kicks from everyones' names."

"Oh my god, Sans."

"hey, don't blame me. blame ebott xof."

"Unload me now."

"what? too frus-tate-d?"

"SANS!"

* * *

"and…done."

It'd taken twelve drafts to get the wording right, but he'd finished his final project: one last note. Sort of a "So Long, And Thanks For All The Nightmares" to the player. Maybe after this, he'd think about his actions.

He was getting ready to upload the lab to the server when his mouse started moving on its own.

"wha…"

It scrolled over to one of the folders on the desktop that the player had made, and pulled out an MP3 file. All it took was looking at the name for Sans to understand.

"heh. okay, then."

He put it in the folder named "Undertale" with his little letter. It was time. He brought up the recorder to make his final address.

"well, according to this computer, it's currently monday, 6:16 am. the player known as alex campbell should be waking up at any moment. if everything's gone right, i should be about to remove myself and this lab from the computer entirely, and uploading it to some online storage site. if i messed up, and you're still somehow listening to this, read the journal and hopefully you can fix my mistakes. as for me, i just wanna take a nice long nap. see ya."

He looked over at the computer. His mouse was already on the upload button without him having to move it.

"heh.

thanks dad."

* * *

'Are you sure you want to upload this file?'

 **Yes  
** No

 **AN: And that's it! Hopefully, within the next day or so, I should post the final epilogue chapter, and then this story is done. I hope I sufficiently explained what the hell is going on in this story. If not, feel free to send me feedback to my Tumblr, sorio99 . tumblr . com .**

 **Now, I'm considering writing more stories, possibly in this universe. So, if you actually took the time to read this, send me a message telling me if you want to see more of this, or if you just want this to finally be done.**

 **Thanks for reading. See you later.**


	9. Chapter 9: The Merciful Finale

'Open Directory: Library'

'Open Folder: Application Support'

'Open Folder: Steam'

'Open Folder: steamapps'

'Open Folder: common'

'Open Folder: Undertale'

'Open File: sucks to be you .docx'

* * *

It took Sans a few seconds to realize he was really back home.

He checked the clock. 6:15 AM. A minute before the kid fell down.

He did it.

He changed his bedroom door's exit to Room77, and he saw Papyrus, laying in his bed, just waking up with a jolt.

"SANS, WHAT…"

He walked over to his brother's bed, and hugged him as tight as he could.

"it's okay, bro. everything's going to be okay.

"we're getting out."

* * *

"Dear Mr. Alex Campbell,

Thank you for beta-testing Undertale Version 2.01! Unfortunately, your usage of the beta, and indeed all versions of Undertale, has been permanently suspended."

* * *

"ME FIRST! ME FIRST"

"All right, Papyrus. Calm down. You'll learn soon enough."

"i still don't get it. i thought our souls were white."

"Well, that's true. However, within that white is a more solid color, similar to humans."

"DAD, YOU'VE TOLD HIM A BAJILLION TIMES. HE'S JUST TOO LAZY TO REMEMBER IT."

"am not. i've got an eid…eidet…"

"An eidetic memory, Sans. And that isn't entirely proven yet, it's just a hypothesis."

"WHATEVER! SOULS NOW, BRAIN STUFF LATER!"

"we don't have brains, bro."

"SANS!"

"Alright, boys, no fighting. Here, Papyrus. Your results are done."

"YAY! SO, IT'S DARK BLUE…WHAT DOES THAT MEAN?"

"blue's integrity, bro."

"AW, I WANTED TO BE BRAVERY!"

"you slept with a nightlight longer than i did, bro."

"Now, now, Sans. Let's not make fun of Papyrus for things he can't control."

"YEAH! BESIDES, I'M THE OLDER ONE, SO YOU GOTTA RESPECT ME!"

"you're still only eleven, bro."

"Sans, don't you want to see your results?

"oh, yeah. gimme."

"SANS, BE POLITE!"

"that'd be the snow calling the skeleton white…huh. cyan."

"Correct. And a rather healthy cyan at that."

"but i hate waiting for stuff."

"Patience doesn't just mean waiting for things that you want. It means being willing to bide your time, wait for an opportunity you want, and weighing all your options before you act."

"you sure do seem to know a lot about patience."

"Of course I do. It's my color as well."

* * *

"The reasons for this suspension include, but are not limited to:

• Failure to recognize sentient behavior.

• Lack of respect for the creator's intentions.

• Expressed intent to manipulate the game's files for little reason.

• General signs of sociopathy expressed beyond acceptable limits.

These problems, while far from exclusive to yourself, nonetheless make you an ill fit for the experience associated with this game."

* * *

"Is it weird if a fictional character you're writing acts differently than you'd expect them to?"

"I don't know. You're the one who writes more. I'd honestly just chalk it up to emerging sentience in fictional characters."

"Huh…you think so?"

"…that was a joke, Toby."

"Oh…right. I knew that. Sorry to wake you, Tem."

"It's fine. What exactly happened?"

"Well, you know Gaster? I decided to kill him off before the game started, but Papyrus jumped in the way."

"Oh no, not Papyrus!"

"I know! I guess it makes some sense, but still."

"Well, how did you try to kill him off?"

"Oh, I just had one of his blasters go off during a random ceremony. Sort of a 'freak accident' 'two days before retirement', you know?"

"…not gonna lie, that's pretty cliché."

"Yeah, and I can work with what happened, but I didn't even think that would happen before I wrote it down."

"Whatever. As long as I still get to draw Papyrus in stupid outfits."

"Of course. I'll try to find a way in-story to bring him back."

"'kay. See ya."

"See you."

* * *

"In the future, when playing games, we would recommend putting a little more thought into what you do and what you say.

After all, you never know when somebody's watching.

Sincerely,

Dr. Sans Aster, PhD."

'Attached file: 3'

"…What the fu-"

 ** _THE END_**

* * *

 **AN: If you don't get the ending, just lookup Entry 17: Dark Darker Yet Darker on Youtube, and it should still be the first result.**


End file.
